内隔墙对开挖前抽水引发软土区地铁深基坑变形的控制效果  

Control effect of cross walls on metro foundation pit deformation induced by pre-excavation dewatering in soft soils

作　　者：曾超峰[1,2] 王硕 宋伟炜 李淼坤 薛秀丽 梅国雄[2] ZENG Chaofeng;WANG Shuo;SONG Weiwei;LI Miaokun;XUE Xiuli;MEI Guoxiong(Hunan Provincial Key Laboratory of Geotechnical Engineering for Stability Control and Health Monitoring,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning,Guangxi 530004,China)

机构地区：[1]湖南科技大学岩土工程稳定控制与健康监测湖南省重点实验室,湖南湘潭411201 [2]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004

出　　处：《岩石力学与工程学报》2021年第6期1277-1286,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51708206,51978261);湖南省自然科学基金资助项目(2020JJ5193)。

摘　　要：目前,基坑领域绝大多数研究均忽略了开挖前抽水引起的围挡侧移,如何有效控制这部分变形对于软土区深基坑施工有较大意义。提出合理布置内隔墙进行变形控制的理念,通过开展基坑抽水模型试验与三维数值分析,探究内隔墙对于限制开挖前抽水引发基坑变形的有效性,并进一步研究不同内隔墙间距对变形控制效果的影响。研究表明,单幅内隔墙的变形控制有一定影响范围(约内隔墙两侧各30 m),内隔墙位置处变形控制效果最强,远离内隔墙位置变形控制效果逐渐减弱;可通过合理设置内隔墙间距(d),利用相邻内隔墙变形限制的叠加效应来控制基坑整体变形。研究发现,当d<5B时(B为基坑宽度),内隔墙对基坑整体变形的限制效果开始显现,当d<3B时,内隔墙将体现较明显的变形限制作用。At present,most studies in the field of foundation pits ignore the wall deflection caused by pre-excavation dewatering(PED). How to effectively control such deformation is of great significance to the construction of deep foundation pits in soft soils. In this study,an idea of rationally arranging cross walls for deformation control is proposed. Through laboratory-scale tests and numerical simulations,the effectiveness of the cross wall in reducing the foundation pit deformation induced by PED is investigated,and the influence of the cross wall spacing on the deformation control effect is discussed. Results show that the deformation control of a single cross wall has a certain range of influence,about 30 m apart from both sides of the cross wall in this paper. The deformation control effect is strongest at the cross wall location and gradually weakens with increasing the distance from the cross wall. It is also indicated that,when the cross wall spacing d is smaller than 5 times the width of the foundation pit B,the restraint effect of the cross walls on the overall pit deformation begins to appear,and that,when d is smaller than 3 B,the cross walls will show apparent effect in restraining pit deformation induced by PED. It is suggested that the overall deformation of the foundation pit can be controlled through the superimposition effect of the deformation restraint of adjacent cross walls by setting a reasonable cross wall spacing.

关 键 词：地基基础 软土地基 基坑降水 围护结构侧移 内隔墙 模型试验 数值模拟 

分 类 号：TU473[建筑科学—结构工程]